Pressure exchangers



Dec. 7, 1965 D. B. SPALDING 3,221,981

PRESSURE EXGHANGERS Filed May 13, 1963 Fla. 2.

United States Patent 3,221,981 PRESSURE EXCHANGERS Dudley Brian Spalding, London, England, assignor to Power Jets (Research 8: Development) Limited, London, England, a iiritish company Filed May 13, 1963, Ser. No. 230,032 Claims priority, application Great Britain, May 17, 1962, 19,146/62 3 Claims. (Cl. 230-69) The present invention relates to pressure exchangers.

A pressure exchanger is herein defined as an apparatus comprising cells in which one gas quantity expands, so compressing another gas quantity with which it is in direct contact, ducting to lead gas at different pressures steadily to and from the cells and means to effect relative motion between the cells and the ducting.

The specification of United States patent application No. 187,500 (now abandoned) describes a pressure exchanger which includes cells of variable volume and means for varying the volume on relative motion between the oells and the ducting. The description has been carried over into continuing application Serial No. 280,054. An embodiment of such a pressure exchanger comprises an outer tubular member and an inner tubular member arranged eccentrically with respect to each other. One of the members carries walls which extend radially to the other member, the wall-carrying member and the walls together forming a rotatable cell ring.

To obtain maximum driving power from the cell ring when the pressure exchanger is in operation, the driving pressure fluid is admitted to the cell or cells of minimum volume. However, if, when the cell ring is stationary, the cell or cells of minimum volume are substantially symmetrical with respect to the inlet through which the pressure fluid is admitted, the cell ring will probably not rotate since the total pressure on each of the walls of the cell or cells will be substantially the same.

It is an object of the present invention to provide means for starting a pressure exchanger of the kind referred to above.

According to the present invention a pressure exchanger includes an outer tubular member having an internal circumferential surface, an inner member having an external circumferential surface mounted within the tubular member, a plurality of walls carried by one of said members and extending from the circumferential surface thereof towards the circumferential surface of the other of said members to define therebetween a plurality of open-ended cells, end-plate structure effective to close the ends of the cells but having ports therein, including a port to convey fluid at a high pressure and a port to convey fluid at a lower pressure, means to rotate the wallcarrying member, the inner and outer members being eccentric to each other, the arrangement being such that the distance between their opposed circumferential surfaces is a minimum adjacent the port to convey fluid at a high pressure and is a maximum adjacent the port to convey fluid at a lower pressure and the end-plate structure having a subsidiary port to convey fluid to the cells, which port is located to follow, in the desired direction of rotation of the wall-carrying member, the port to convey fluid at a high pressure but precede the port to convey fluid at a lower pressure.

Preferably the subsidiary port and the port to convey fluid at a high pressure are supplied with pressure fluid from a common duct.

Advantageously a valve is provided to shut off the supply of pressure fluid to the subsidiary port when the wall-carrying member is rotating.

An embodiment of the invention will now be described 3,221,981 Patented Dec. 7, 1965 by way of example reference being made to the accompanying diagrammatic drawing in which:

FIGURE 1 is a cross-sectional view of a pressure exchanger according to the invention; and

FIGURE 2 is a developed view of the pressure exchanger of FIGURE 1.

The pressure exchanger includes a rotor 1 carrying a plurality of radially slidable walls 2 arranged around the periphery thereof to form a cell ring. The rotor 1 rotates about an axis 3 spaced from the axis 4 of a stationary shroud 5 circumferentially surrounding the cell ring. As can be seen from the drawing, on rotation of the cell ring in a clock-wise direction the cells progressively decrease in volume from a position '7 of maximum volume to a position 6 of minimum volume. For simplicity a change in cell volume has been represented by a change in axial length of the cell walls, thus the cell of minimum volume is bounded by the shortest cell walls.

A port 8, shown in broken lines in FIGURE 1, admits pressure fluid to the cells of minimum volume and a port 9, also shown in broken lines in FIGURE 1, receives pressure fluid from the cells of maximum volume. A subsidiary port 10 admits pressure fluid to a cell spaced away from the cells of minimum volume in the direction of rotation of the cell ring, that is in the direction of increasing cell volume.

A duct 11 supplies pressure fluid to the port 8 and a duct 12, branched from the duct 11, supplies pressure fluid to the port 10. A valve 13 is located in the duct 12 and is lightly loaded to permit passage of pressure fluid one way only, i.e., towards the port 10.

If pressure fluid were supplied only to the cells of minimum volume as shown in the drawing, the cell ring would probably remain stationary since the forces acting on the walls of these cells would exactly counterbalance each other. On supplying pressure fluid to a cell spaced away from the cells of minimum volume in the direction of rotation of the cell ring, the latter commences to rotate since the cell wall of this cell spaced furthest from the cells of minimum volume is of larger area than its opposed wall and therefore the force thereon will also be larger with the result that there is a torque tending to rotate the cell ring.

To operate the pressure exchanger according to the invention pressure fluid is supplied to the duct 11 which directs part of this fluid into the cell or cells of minimum volume via the port 8. A part of the pressure fluid is bled off from the duct 11 through the branch duct 12 and flows past the valve 13 into the cell or cells opposite the subsidiary port 10. As explained above there is now an unbalance of forces within the cells of the cell ring and the latter commences to rotate. As the speed of the cell ring increases the pressure within each cell builds up until the pressure within the cell coming opposite the subsidiary port 10 is higher than the pressure of the fluid supplied to that port through the branch duct 12. The valve 13 is thus caused to close and the pressure exchanger continues to function in the normal manner.

If desired the valve 13 may be manually controlled the operator holding the valve open during starting and subsequently releasing it to return to its closed position under spring pressure.

What I claim is:

1. A pressure exchanger including:

(a) an outer tubular member having an internal circumferential surface,

(b) an inner member having an external circumferential surface mounted within the tubular member,

(c) a plurality of walls carried by one of said members and extending from the circumferential surface thereof to positions adjacent the circumferential surface of the other of said members to define therebetween a plurality of open-ended cells the wall-carrying member being constructed to permit the walls to slide therein,

(d) end-plate structure effective to close the ends of the cells but having ports therein, including a port to convey fluid at a high-pressure and a port to convey fluid at a lower-pressure,

(e) means to permit rotation of the wall-carrying member,

(f) the inner and outer members being eccentric to each other, the arrangement being such that the distance between their opposed circumferential surfaces is a minimum adjacent the port to convey fluid at a high-pressure and is a maximum adjacent the port to convey fluid at a lower-pressure, the walls sliding inwardly and outwardly of the wall-carrying member as the distance between said surfaces varies from a minimum to a maximum, and

(g) the end-plate structure having a subsidiary port to convey fluid to the cells, which port is located to follow, in the desired direction of rotation of the wall-carrying member, the port to convey fluid at a high-pressure but precede the port to convey fluid at a lower-pressure. 5 2. A pressure exchanger according to claim 1 wherein the subsidiary port and the port to convey fluid at a highpressure are supplied with pressure fluid from a common duct.

3. A pressure exchanger according to claim 1 wherein a valve is provided to shut off the supply of pressure fluid to the subsidiary port when the wall-carrying member is rotating.

References Cited by the Examiner UNITED STATES PATENTS 6/1936 Lcbre. 

1. A PRESSURE EXCHANGER INCLUDING: (A) AN OUTER TUBULAR MEMBER HAVING AN INTERNAL CIRCUMFERENTIAL SURFACE, (B) AN INNER MEMBER HAVING AN INTERNAL CIRCUMFERENTIAL SURFACE MOUNTED WITHIN THE TUBULAR MEMBER, (C) A PLURALITY OF WALLS CARRIED BY ONE OF SAID MEMBERS AND EXTENDING FROM THE CIRCUMFERENTIAL SURFACE THEREOF TO POSITIONS ADJACENT THE CIRCUMFERENTIAL SURFACE OF THE OTHER OF SAID MEMBERS TO DEFINE THEREBETWEEN OF A PLURALITY OF OPEN-ENDED CELLS THE WALL-CARRYING MEMBER BEING CONSTRUCTED TO PERMIT THE WALLS TO SLIDE THEREIN, (D) END-PLATE STRUCTURE EFFECTIVE TO CLOSE THE ENDS OF THE CELLS BUT HAVING PORTS THEREIN, INCLUDING A PORT TO CONVEY FLUID AT A HIGH-PRESSURE AND A PORT TO CONVEY FLUID AT A LOWER-PRESSURE, (E) MEANS TO PERMIT ROTATION OF THE WALL-CARRYING MEMBER, (F) THE INNER AND OUTER MEMBERS BEING ECCENTRIC TO EACH OTHER, THE ARRANGEMENT BEING SUCH THAT THE DISTANCE BETWEEN THEIR OPPOSED CIRCUMFERENTIAL SURFACES IS A MINIMUM ADJACENT THE PORT TO CONVEY FLUID AT A HIGH-PRESSURE AND IS A MAXIMUM ADJACENT THE PORT TO CONVEY FLUID AT A LOWER-PRESSURE, THE WALLS SLIDING INWARDLY AND OUTWARDLY OF THE WALL-CARRYING MEMBER AS THE DISTANCE BETWEEN SAID SURFACES VARIES FROM A MINIMUM TO A MAXIMUM, AND (G) THE END-PLATE STRUCTURE HAVING A SUBSIDIARY PORT TO CONVEY FLUID TO THE CELLS, WHICH PORT IS LOCATED TO FOLLOW, IN THE DESIRED DIRECTION OF ROTATION OF THE WALL-CARRYING MEMBER, THE PORT TO CONVEY FLUID AT A HIGH-PRESSURE BUT PRECEDE THE PORT TO CONVEY FLUID AT A LOWER-PRESSURE. 